Infix To Postfix

class Stack:
    def __init__(self):
        self._stek = []

    def isEmpty(self):
        if len(self._stek) != 0:
            return False
        return True

    def push(self, element):
        self._stek.append(element)

    def pop(self):
        return self._stek.pop()

    def top(self):
        return self._stek[-1]

    def prikazi(self):
        for i in self._stek:
            print str(i) + " ",
        print

    def __len__(self):
        return len(self._stek)

niz = Stack()
infix = raw_input()

postfix = ""

for i in infix:
    if "0" <= i <= "9":
        postfix += i
    else:
        if ((len(niz)>0) and (i=="+" or i=="-") and (niz.top()=="*" or niz.top()=="/")):
            while len(niz) > 0:
                postfix += str(niz.pop())
        elif (len(niz)>0 and ((i=="-" and (niz.top()=="+" or niz.top()=="-")) or (i=="+" and niz.top()=="-"))):
                postfix += str(niz.pop())
        elif (len(niz)>0 and ((i=="/" and (niz.top()=="*" or niz.top()=="/")) or (i=="/" and niz.top()=="/") or (i=="*" and niz.top()=="/"))):
                postfix += str(niz.pop())
        niz.push(i)

while len(niz) > 0:
    postfix += str(niz.pop())

print postfix

input()